Is the word vírus the same in Brazilian and European Portuguese?

Yes

The spelling, meaning, and grammatical function of the word "vírus" are identical in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Brazilian Portuguese, the vowels tend to be more open and clearly articulated. In Continental Portuguese, unstressed vowels are often more closed or reduced, which affects the overall rhythm and phonetic realization of the word, though the fundamental sound of the stressed syllable remains recognizable.

Brazilian Portuguese Examples

1. O meu celular pegou um vírus. (My cell phone caught a virus.)
2. O médico disse que é um vírus de gripe. (The doctor said it is a flu virus.)
3. Tome cuidado para não baixar vírus no computador. (Take care not to download viruses on the computer.)
4. Esse vírus é muito perigoso. (This virus is very dangerous.)
5. O antivírus está desatualizado. (The antivirus is outdated.)

Continental Portuguese Examples

1. O meu telemóvel apanhou um vírus. (My mobile phone caught a virus.)
2. O médico disse que é um vírus da gripe. (The doctor said it is a flu virus.)
3. Tem cuidado para não descarregares vírus no computador. (Be careful not to download viruses on the computer.)
4. Este vírus é muito perigoso. (This virus is very dangerous.)
5. O antivírus está desatualizado. (The antivirus is outdated.)